Structure for mounting rubber printing plates for printing on corrugated board and the like



3,119,330 FOR L. S. KUNETKA OUNTING Jan. 28, 1964 E FOR M TING ON RUB E; PRINTING PLATES CORRUGATED ARD AND THE LIKE 2 Sheets-Sheet 1 STRUCTUR PRIN Filed Feb. 20, 1962 E W. 3 M M 3,119,330 FOR Jan. 28, 1 L. s. KUNETKA STRUCTURE FOR MOUNTING RUBBER PRINTING PLATES PRINTING ON CORRUGATED BOARD AND THE LIKE Filed Feb. 20, 1962 2 Sheets-Sheet 2 I V INVENTOR. '1evxced%mf%a United States Patent F 3,119,330 TRUCTURE FDR MOUNTING RUBBER PTENG s PLATES FGR PRINTENG 8N C(BRRUGATED BDARD AND THE LIKE Lawrence S. Kunetka, Ni) Lake Shore Drive, Chicago 11, El. Filed Feb. 20, W62, Ser. No. 174,6tl2. 3 Claims. 31. loi -382) This invention relates generally to the graphic arts and more particularly is concerned with an improved mounting structure for rubber printing plates of the kind used to print on corrugated paperboard or the like.

This application is a continuation-in-part of applica- .tion Serial No. 189,379, filed May 11, 1961 of the same title.

In the above referred to application, a structure is disclosed and claimed which basically consists of a relatively thin sheet of latex impregnated paperboard having a lighttransmitting non-porous film secured overlying a surface of the sheet. The surface of the sheet is provided with a visible grid which is covered and protected by the film so that rubber printing plate can accurately to positioned on the backing sheet.

The application teaches the securement of portions of such backing structures to wooden printing rollers as by stapling, witi the grid of the printing roller in alignment with the grid on the backing structure. The user thereafter secures the plates by adhesive, adhesive tape or the like to the surface of the backing sheet.

Many advantages were attributed to the backing structure there described, such as flexibility, ease of peeling, etc.

Some of the objects of this invention are concerned with achieving all of the advantages set forth in the previous application in connection with the backing there described and claimed.

One difiiculty was experienced with the previous backing structure which is overcome by the invention herein. In washing printing plates or using solvents and chemicals of any kind on the roller when the backing structure was secured thereto, it was found that despite precautions, the highly penetrating chemicals and washes would seep into the base of the backing structure, that is, into the latex impregnated paper, thereby causing swelling, unevenness and often de-larnination of the film from the backing.

The principal object of the invention lies in the provision of the backing which will be substantially impervious to the washes, solvents and chemicals used in the graphic arts and in connection therewith providing a backing structure which has a protective film on its rear surface of the same nature as that on its front surface.

A further object flows from the achievement of a printing roller completely covered with the sheeting of the construction of the backing structure.

Other objects will appear as a description of the invention proceeds in connection with which preferred embodiments are illustrated and described in detail.

FIG. 1 is a fragmentary perspective view of a wooden printing roller havin a backing structure mounting a rubber printing plate embodying the invention, the same being secured on the circumference of the said roller.

FIG. 2 is an enlarged fragmentary plan view of the said roller showing the structure of FIG. 1 secured thereon.

FIG. 3 is a fragmentary sectional view taken through the structure of FIG. 1 and showing the various layers of the materials applied to the printing roller in greatly exaggerated dimension.

FIG. 4 is a sectional view taken generally of a steel printing roller showing the manner of completely cover- 3,ll9,33fi Patented Jan. 28, 1964 ing the steel roller with a sheet of backing material constructed in accordance with the invention.

F IG. 5 is a similar view but showing the application of the backing material to a wooden roller.

The reference character 20 represents a wooden printing roller or cylinder of a printing press customarily used for printing on corrugated paper or the like. Ordinarily the circumference of the roller 29 is scored and otherwise provided with a grid or ruled surface 24 which is utilized to position a printing plate properly on the circumference of the roller.

A printing plate assembly designated generally by reference character 26 is secured as a unit on the printing roller Zll. This assembly comprises a rubber printing plate 28 adhesively secured on the backing member 34). The backing member is formed of sheet material comprising the structure of the invention.

As seen in FIG. 3, the rubber printing plate 28 comprises a sheet 32 of rubber or rubber-like material, the upper surface of which has been cut or otherwise provided with a printing face of type 34 designed to transfer a predetermined imprint of indicia to a surface of corrugated paperboard. The sheet 32 is :afiixed on a very thin sheet 36 of rubber by means of a coating of pressure sensitive adhesive 38, the opposite or outer surface of the rubber sheet 35 also being coated with pressure sensitive adhesive 3? which may be similar to the adhesive 38. The printing plate 28 is secured releasably on the backing member 3% by means of a coating of adhesive 39. Any suitable pressure sensitive adhesive may be employed such as a latex cement or glue. The printing plate 28 may be obtained from a supplier already coated with adhesive 39 or may be coated by the printer preparatory to using the same.

The backing member 31} includes a specially constructed paperboard sheet it) which is produced from a mixture of latex and paper fibersblended in a beater in accordance with well known techniques used in the manufacture of paper. The sheet 4% is thin and flexible to a degree heretofore not employed or considered feasible for backing sheet materials of this character.

The structure of the application above referred to had one surfacefiZ of the latex impregnated paperboard sheet if) provided with a transparent or translucent plastic film 4-4 thereon in a manner which did not reduce the flexibility of the backing member 30 or materially increase the thickness thereof. In accordance with the disclosure of the said application, the plastic film 44 was a very hard, non-porous sheet of polyethylene terephthalate, commonly known as mylar. It was laminated to sheet 40 or formed by deposition of a vinyl plastic material over the surface 42 in liquid form which subsequently is cured to seal the surface 42. This provided an ideal surface for the rubber printing plate giving rise to the advantages described in the said application.

In accordance with the disclosure of the said application, the backing member 30 also has a printed grid or ruled surface provided thereon which corresponds to the grid of ruled surface 24 of a printing roll 26). The grid of the backing member can be provided with suitable lines 46 printed or otherwise applied on the surface 4-2 of the sheet 40 which will be covered by the plastic film 44. In this manner, obliteration, erasure or wearing away of the grid was prevented by the film 44. Lines 46 forming the grid of the backing member are visible through the normally transparent or translucent film 44.

An additional plastic film identical in composition to the plastic film 44 is shown at 64) secured to the bottom surface of the sheet member 49 by adhesive 62 in the same manner as the film 44 is secured. The effect of this additional film oil is to seal the backing member 39 against chemicals, solvents and washes normally used on printing presses and prevent de-larnination, buckling, swelling and the like.

It has been found that the exposed edge of the backing structure 39 has substantially no eifect to absorb the washes or solvents and hence the entire backing structure is substantially impervious to these washes and solvents.

If desired, the backing structure 3% may be used in the same manner as that of the application above described; namely, it may be secured to the surface of the printing roller 2'3 as shown in FIG. 2 by staples 48, after which the printing plate 28 may be attached either by adhering the same through the use of adhesives or by the use of pressure sensitive adhesive tape 58 securing the same around the borders thereof. The indexing device 50 may also be used in connection therewith.

Inasmuch as the backing material described, namely that which has a coating both front and back of the impervious film, is of a more permanent character, it has been found useful to convert rollers which have not been capable of use for the mounting of rubber plates to such use. For example, there are steel rollers which have been used for mounting forms but which are incapable of use with rubber plates, due to the difficulty, of attaching the plates and repeatedly stripping the plates from the roller.

In FIG. 4, there is illustrated in sectional view, the steel roller 7 0 having an axial groove in its circumference as shown in 72. Some form of clamping member which may be represented by the bar 74 is used with rollers of this type to secure some form of covering thereon. In this instance, the entire roller is covered by sheet member 76 which is of the construction of the backing material 30. The free ends of the sheet member 76 are overlapped in the groove 72 and clamped in place by the clamping device 74. Thereafter, the roller may be used as a base upon which to secure the rubber printing plate 28. The plates may be readily removed, replaced and the roller may be subjected to the solvents and washes which would normally cause some difficulty with previous backing materials. The surface of the roller will have exactly the same appearance as the surface of the roller 20 in FIG. 1 but there will be no need for the use of staples or any other attaching means, since instead of using an additional sheet member of the backing material 30, the rubber plates may be secured directly to the surface of the roller.

After some extended use in which the surface may 4 become worn, it is a simple matter to remove the sheet 76 and replace it with another.

in PEG. 5, a wooden roller 78 is shown which has had the sheet member 8%) exactly'the same as sheet member 76 secured around the entire circumference thereof and held in place with a suitable fastening means such as the staples or the like, as shown at 82. The wooden roller at 78 may be provided with some form of clamping means also to hold the sheet member 89 in place.

It is believed that the invention has been sufliciently described such as to enable those skilled in the art to understand the same and practice the same. Variations are capable of being made without departing from the spirit or scope of the invention as described in the appended claims.

What it is desired to secure by Letters Patent of the United States is:

1. A unitary backing structure for a rubber printing plate which comprises a single-ply, flexible, latex impregnated sheet of paperboard having a synthetic plastic film permanently secured overlying the top and bottom surfaces of the sheet which is impervious to conventional printing inks and solvents, and a grid interposed between the film and one surface of the sheet of paperboard, visible through the film.

2. A backing structure as described in claim 1 in which said plastic film, in each instance, comprises a thin sheet of polyethylene terephthalate.

3. A unitary backing structure for a rubber printing plate which comprises a single-ply, flexible, latex impregnated sheet of paperboard having a polyethylene terephthalate film secured overlying the top and bottom surfaces of the sheet which is impervious to conventional printing inks and solvents, and index markings visible through said film on one surface of the sheet corresponding to index markings on a conventional printing roll whereby said backing structure can be installed on the printing roll in any one of a plurality of locations with said markings in registry.

References Cited in the file of this patent UNITED STATES PATENTS 1,531,554 Harley Mar. 31, 1925 1,799,217 De Cew Apr. 7, 1931 2,116,066 Elliot May 3, 1938 2,294,879 Aifelder Sept. 8, 1942 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N00 3 11%330 January 28 1964 Lawrence S, Kunetka It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1 line .23, for "to" read be n Signed and sealed this 16th day of June 19640 (SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Anesting Officer Commissioner of Patents 

3. A UNITARY BACKING STRUCTURE FOR A RUBBER PRINTING PLATE WHICH COMPRISES A SINGLE-PLY, FLEXIBLE, LATEX IMPREGNATED SHEET OF PAPERBOARD HAVING A POLYETHYLENE TEREPHTHALATE FILM SECURED OVERYLYING THE TOP AND BOTTOM SURFACES OF THE SHEET WHICH IS IMPREVIOUS TO CONVENTIONAL PRINTING INKS AND SOLVENTS, AND INDEX MARKINGS VISIBLE THROUGH SAID FILM ON ONE SURFACE OF THE SHEET CORRESPONDING TO INDEX MARKINGS ON A CONVENTIONAL PRINTING ROLL WHEREBY SAID BACKING STRUCTURE CAN BE INSTALLED ON THE PRINTING ROLL IN ANY ONE OF A PLURALITY OF LOCATIONS WITH SAID MARKINGS IN REGISTRY. 